//
//  SKGrayscaleContrastFilter.h
//  Gastrosoph
//
//  Created by 张明磊 on 12-10-22.
//  Copyright (c) 2012年 __MyCompanyName__. All rights reserved.
//

#import "GPUImageFilter.h"

extern NSString *const kGrayscaleContrastFragmentShaderString;

/** Converts an image to grayscale (a slightly faster implementation of the saturation filter, without the ability to vary the color contribution)
 */
@interface SKGrayscaleContrastFilter : GPUImageFilter
{
    GLint intensityUniform;
    
	GLint slopeUniform;
}

@property(readwrite, nonatomic) CGFloat intensity; 

@end
